Gata1 is required for the maintenance of the erythroid compartment in adult mice. (A) FACS analysis of the erythroid surface markers Ter119 and CD71. Expression was examined in single cell suspensions prepared from the BM, spleen, and peripheral blood of Gata1^fl/y::Tx-Cre (KO-Tx) and WT mice at 4 weeks after Tx treatment. RI, RII, RIII, and RIV represent cell fractions as indicated in Figure 1E and “Results.” The mean plus or minus SD of the percentage of gated live (7AAD⁻) cells in each region is indicated. (B) BM sections (left, hematoxylin and eosin staining, arrowheads indicate megakaryocytes [M]) and cytospins (right, Wright-Giemsa staining, arrowheads indicate neutrophils) of KO-Tx and WT mice. Original magnification ×100. (C) Spleen sections of KO-Tx and WT mice stained with benzidine (left, erythroid cells stained brown) or acetylcholinesterase (right, megakaryocytes stained brown). (D) CFUe and BFUe assays on BM cells. Average and standard deviation are shown (n ≥ 3). (E) FACS analysis of hanging drop cultures of BM cells using standard conditions (HD ST) and of BM cells labeled with CFSE (HD CFSE). Average and SD are shown (n ≥ 3).